/*
 * The Apache Software License, Version 1.1 Copyright (c) 2001-2004 Caucho
 * Technology, Inc. All rights reserved. Redistribution and use in source and
 * binary forms, with or without modification, are permitted provided that the
 * following conditions are met: 1. Redistributions of source code must retain
 * the above copyright notice, this list of conditions and the following
 * disclaimer. 2. Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution. 3. The
 * end-user documentation included with the redistribution, if any, must include
 * the following acknowlegement: "This product includes software developed by
 * the Caucho Technology (http://www.caucho.com/)." Alternately, this
 * acknowlegement may appear in the software itself, if and wherever such
 * third-party acknowlegements normally appear. 4. The names "Hessian", "Resin",
 * and "Caucho" must not be used to endorse or promote products derived from
 * this software without prior written permission. For written permission,
 * please contact info@caucho.com. 5. Products derived from this software may
 * not be called "Resin" nor may "Resin" appear in their names without prior
 * written permission of Caucho Technology. THIS SOFTWARE IS PROVIDED ``AS IS''
 * AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE. @author Scott Ferguson
 */

package com.caucho.hessian.client;

import com.caucho.hessian.io.*;
import com.caucho.services.server.*;

import java.io.*;
import java.util.logging.*;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.WeakHashMap;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

/**
 * Proxy implementation for Hessian clients. Applications will generally use
 * HessianProxyFactory to create proxy clients.
 */
public class HessianProxy implements InvocationHandler, Serializable
{
	private static final Logger log = Logger.getLogger(HessianProxy.class
			.getName());

	protected HessianProxyFactory _factory;

	private WeakHashMap<Method, String> _mangleMap = new WeakHashMap<Method, String>();

	private Class<?> _type;

	private URL _url;

	/**
	 * Protected constructor for subclassing
	 */
	protected HessianProxy(URL url, HessianProxyFactory factory)
	{
		this(url, factory, null);
	}

	/**
	 * Protected constructor for subclassing
	 */
	protected HessianProxy(URL url, HessianProxyFactory factory, Class<?> type)
	{
		_factory = factory;
		_url = url;
		_type = type;
	}

	/**
	 * Returns the proxy's URL.
	 */
	public URL getURL()
	{
		return _url;
	}

	/**
	 * Handles the object invocation.
	 * 
	 * @param proxy
	 *            the proxy object to invoke
	 * @param method
	 *            the method to call
	 * @param args
	 *            the arguments to the proxy object
	 */
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable
	{
		String mangleName;

		synchronized (_mangleMap)
		{
			mangleName = _mangleMap.get(method);
		}

		if (mangleName == null)
		{
			String methodName = method.getName();
			Class<?>[] params = method.getParameterTypes();

			// equals and hashCode are special cased
			if (methodName.equals("equals") && params.length == 1
					&& params[0].equals(Object.class))
			{
				Object value = args[0];
				if (value == null || !Proxy.isProxyClass(value.getClass()))
					return Boolean.FALSE;

				Object proxyHandler = Proxy.getInvocationHandler(value);

				if (!(proxyHandler instanceof HessianProxy))
					return Boolean.FALSE;

				HessianProxy handler = (HessianProxy) proxyHandler;

				return new Boolean(_url.equals(handler.getURL()));
			}
			else if (methodName.equals("hashCode") && params.length == 0)
				return new Integer(_url.hashCode());
			else if (methodName.equals("getHessianType"))
				return proxy.getClass().getInterfaces()[0].getName();
			else if (methodName.equals("getHessianURL"))
				return _url.toString();
			else if (methodName.equals("toString") && params.length == 0)
				return "HessianProxy[" + _url + "]";

			if (!_factory.isOverloadEnabled())
				mangleName = method.getName();
			else
				mangleName = mangleName(method);

			synchronized (_mangleMap)
			{
				_mangleMap.put(method, mangleName);
			}
		}

		InputStream is = null;
		HessianConnection conn = null;

		try
		{
			if (log.isLoggable(Level.FINER))
				log.finer("Hessian[" + _url + "] calling " + mangleName);

			conn = sendRequest(mangleName, args);

			is = conn.getInputStream();

			if (log.isLoggable(Level.FINEST))
			{
				PrintWriter dbg = new PrintWriter(new LogWriter(log));
				HessianDebugInputStream dIs = new HessianDebugInputStream(is,
						dbg);

				dIs.startTop2();

				is = dIs;
			}

			AbstractHessianInput in;

			int code = is.read();

			if (code == 'H')
			{
				int major = is.read();
				int minor = is.read();

				in = _factory.getHessian2Input(is);

				Object value = in.readReply(method.getReturnType());

				return value;
			}
			else if (code == 'r')
			{
				int major = is.read();
				int minor = is.read();

				in = _factory.getHessianInput(is);

				in.startReplyBody();

				Object value = in.readObject(method.getReturnType());

				if (value instanceof InputStream)
				{
					value = new ResultInputStream(conn, is, in,
							(InputStream) value);
					is = null;
					conn = null;
				}
				else
					in.completeReply();

				return value;
			}
			else
				throw new HessianProtocolException("'" + (char) code
						+ "' is an unknown code");
		}
		catch (HessianProtocolException e)
		{
			throw new HessianRuntimeException(e);
		}
		finally
		{
			try
			{
				if (is != null)
					is.close();
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}

			try
			{
				if (conn != null)
					conn.destroy();
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}
		}
	}

	protected String mangleName(Method method)
	{
		Class<?>[] param = method.getParameterTypes();

		if (param == null || param.length == 0)
			return method.getName();
		else
			return AbstractSkeleton.mangleName(method, false);
	}

	/**
	 * Sends the HTTP request to the Hessian connection.
	 */
	protected HessianConnection sendRequest(String methodName, Object[] args)
			throws IOException
	{
		HessianConnection conn = null;

		conn = _factory.getConnectionFactory().open(_url);
		boolean isValid = false;

		try
		{
			addRequestHeaders(conn);

			OutputStream os = null;

			try
			{
				os = conn.getOutputStream();
			}
			catch (Exception e)
			{
				throw new HessianRuntimeException(e);
			}

			if (log.isLoggable(Level.FINEST))
			{
				PrintWriter dbg = new PrintWriter(new LogWriter(log));
				HessianDebugOutputStream dOs = new HessianDebugOutputStream(os,
						dbg);
				dOs.startTop2();
				os = dOs;
			}

			AbstractHessianOutput out = _factory.getHessianOutput(os);

			out.call(methodName, args);
			out.flush();

			conn.sendRequest();

			isValid = true;

			return conn;
		}
		finally
		{
			if (!isValid && conn != null)
				conn.destroy();
		}
	}

	/**
	 * Method that allows subclasses to add request headers such as cookies.
	 * Default implementation is empty.
	 */
	protected void addRequestHeaders(HessianConnection conn)
	{
		conn.addHeader("Content-Type", "x-application/hessian");

		String basicAuth = _factory.getBasicAuth();

		if (basicAuth != null)
			conn.addHeader("Authorization", basicAuth);
	}

	/**
	 * Method that allows subclasses to parse response headers such as cookies.
	 * Default implementation is empty.
	 * 
	 * @param conn
	 */
	protected void parseResponseHeaders(URLConnection conn)
	{
	}

	public Object writeReplace()
	{
		return new HessianRemote(_type.getName(), _url.toString());
	}

	static class ResultInputStream extends InputStream
	{
		private HessianConnection _conn;

		private InputStream _connIs;

		private AbstractHessianInput _in;

		private InputStream _hessianIs;

		ResultInputStream(HessianConnection conn, InputStream is,
				AbstractHessianInput in, InputStream hessianIs)
		{
			_conn = conn;
			_connIs = is;
			_in = in;
			_hessianIs = hessianIs;
		}

		public int read() throws IOException
		{
			if (_hessianIs != null)
			{
				int value = _hessianIs.read();

				if (value < 0)
					close();

				return value;
			}
			else
				return -1;
		}

		public int read(byte[] buffer, int offset, int length)
				throws IOException
		{
			if (_hessianIs != null)
			{
				int value = _hessianIs.read(buffer, offset, length);

				if (value < 0)
					close();

				return value;
			}
			else
				return -1;
		}

		public void close() throws IOException
		{
			HessianConnection conn = _conn;
			_conn = null;

			InputStream connIs = _connIs;
			_connIs = null;

			AbstractHessianInput in = _in;
			_in = null;

			InputStream hessianIs = _hessianIs;
			_hessianIs = null;

			try
			{
				if (hessianIs != null)
					hessianIs.close();
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}

			try
			{
				if (in != null)
				{
					in.completeReply();
					in.close();
				}
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}

			try
			{
				if (connIs != null)
				{
					connIs.close();
				}
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}

			try
			{
				if (conn != null)
				{
					conn.close();
				}
			}
			catch (Exception e)
			{
				log.log(Level.FINE, e.toString(), e);
			}
		}
	}

	static class LogWriter extends Writer
	{
		private Logger _log;

		private Level _level = Level.FINEST;

		private StringBuilder _sb = new StringBuilder();

		LogWriter(Logger log)
		{
			_log = log;
		}

		public void write(char ch)
		{
			if (ch == '\n' && _sb.length() > 0)
			{
				_log.fine(_sb.toString());
				_sb.setLength(0);
			}
			else
				_sb.append((char) ch);
		}

		public void write(char[] buffer, int offset, int length)
		{
			for (int i = 0; i < length; i++)
			{
				char ch = buffer[offset + i];

				if (ch == '\n' && _sb.length() > 0)
				{
					_log.log(_level, _sb.toString());
					_sb.setLength(0);
				}
				else
					_sb.append((char) ch);
			}
		}

		public void flush()
		{
		}

		public void close()
		{
			if (_sb.length() > 0)
				_log.log(_level, _sb.toString());
		}
	}
}
